1. Field of the Invention
This invention relates to the routing and tracking of a sensor platform to observe a region of interest while avoiding obstacles.
2. Description of the Related Art
Manned and unmanned aircraft are used to observe and sense a region of interest on the ground to generate maps, surveil the region etc. In a typical scenario the aircraft maintains (or attempts to maintain) a fixed height above the ground and projects a constant sensor footprint onto the ground. The sensor footprint may be directly below the aircraft, forward or behind but is perpendicular to the flight path when projected onto the lateral-vertical plane of the aircraft.
Typically, the aircraft is routed along a flight path that follows a raster-scan pattern back-and-forth to cover a rectangular region of interest. The aircraft senses a rectangular swath equal to the width of the sensor footprint. The swaths may overlap, say 10%. The flight path is represented as straight-line segments along each swath and connecting the end of one swath to the next. Because of the kinematic constraints on an aircraft (e.g., its turn radius), the aircraft cannot typically make the sharp turns at the end of each scan. The aircraft's tracking system will attempt to stay on the path but will inevitably overshoot the turns before returning to the path. As a result, either portions of the region of interest may not be sensed or the search area has to be oversized to accommodate for the limitations of the aircraft. This also increases the total path length of the aircraft.
If there is an excluded area within the region of interest in which the aircraft is not allowed to fly, a person manually subdivides the rectangular ROI into multiple smaller rectangular regions around the excluded area. The aircraft is routed along a path that raster scans each of the individual smaller rectangular sub-regions. The person manually determines a suitable way to subdivide the initial ROI into the smaller rectangular sub-regions and the order in which to observe each sub-region. The sub-regions must be bounded away from the excluded areas to avoid having the aircraft cross into the excluded areas when it turns at the end of each raster scan line. This approach must either tolerate voids in the sensed outputs or overlap the sub-regions. This increases the total path of the aircraft.